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Background: Coagulation factor XIII is a transglutaminase with a tetrameric structure which consists of two identical pre enzyme subunits (FXIIIA) and two carrier protein subunits (FXIIIB). FXIII Val34Leu polymorphism has a high prevalence in Caucasians. The prevalence of FXIII Val34Leu polymorphism in Iranian patients was investigated in this study by PCR-RFLP method.

Materials and Methods: In this descriptive study blood samples of 213 patients referred to the central laboratory of IBTO were assessed by DNA extraction and polymerase chain reaction (PCR). Then the genotypes of this polymorphism were identified by RFLP method in the presence of restricted enzyme. Data analyzed by SPSS 11.5 software and X2 Test.

Results: The prevalence of Val34Leu polymorphism was 24.4% (22.06% heterozygote and 2.34% homozygote and 13.07% of Leu allele frequency). No relationship was seen between the polymorphism and sex.

Conclusion : The high prevalence of FXIII Val34Leu polymorphism in Iranian thrombotic patients in comparison with reports from other Asian countries confirms the ethnic heterogenecity of this polymorphism which is not influenced by sex.